refactor the confirmation option

Signed-off-by: Haoliang Yue <yuehaoliang@microsoft.com>

cmd/oras/internal/util/util.go → cmd/oras/internal/option/confirmation.go

@@ -13,14 +13,28 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package util
+package option
 
 import (
 	"fmt"
 	"strings"
+
+	"github.com/spf13/pflag"
 )
 
-func AskForComfirmation() (bool, error) {
+// Confirmation option struct.
+type Confirmation struct {
+	Confirmed bool
+}
+
+// ApplyFlags applies flags to a command flag set.
+func (opts *Confirmation) ApplyFlags(fs *pflag.FlagSet) {
+	fs.BoolVarP(&opts.Confirmed, "yes", "y", false, "do not prompt for confirmation")
+}
+
+func (opts *Confirmation) AskForComfirmation(message string) (bool, error) {
+	fmt.Print(message)
+
 	var response string
 	_, err := fmt.Scanln(&response)
 	if err != nil {
@@ -33,7 +47,6 @@ func AskForComfirmation() (bool, error) {
 	case "n", "no":
 		return false, nil
 	default:
-		fmt.Println("please type (y)es or (n)o and then press enter")
-		return AskForComfirmation()
+		return opts.AskForComfirmation(message)
 	}
 }

cmd/oras/internal/option/descriptor.go

@@ -0,0 +1,43 @@
+/*
+Copyright The ORAS Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package option
+
+import (
+	"encoding/json"
+	"fmt"
+
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/spf13/pflag"
+)
+
+// Descriptor option struct.
+type Descriptor struct {
+	OutputDescriptor bool
+}
+
+// ApplyFlags applies flags to a command flag set.
+func (opts *Descriptor) ApplyFlags(fs *pflag.FlagSet) {
+	fs.BoolVarP(&opts.OutputDescriptor, "descriptor", "", false, "output the descriptor")
+}
+
+// Marshal returns the JSON encoding of descriptor.
+func (opts *Descriptor) Marshal(desc ocispec.Descriptor) ([]byte, error) {
+	b, err := json.Marshal(desc)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal descriptor: %w", err)
+	}
+	return b, err
+}

cmd/oras/internal/option/pretty.go

@@ -0,0 +1,51 @@
+/*
+Copyright The ORAS Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package option
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+
+	"github.com/spf13/pflag"
+)
+
+// Pretty option struct.
+type Pretty struct {
+	pretty bool
+}
+
+// ApplyFlags applies flags to a command flag set.
+func (opts *Pretty) ApplyFlags(fs *pflag.FlagSet) {
+	fs.BoolVarP(&opts.pretty, "pretty", "", false, "output prettified content")
+}
+
+// Output outputs the prettified content if `--pretty` flag is used. Otherwise
+// outputs the original content.
+func (opts *Pretty) Output(w io.Writer, content []byte) error {
+	if opts.pretty {
+		buf := bytes.NewBuffer(nil)
+		if err := json.Indent(buf, content, "", "  "); err != nil {
+			return fmt.Errorf("failed to prettify: %w", err)
+		}
+		buf.WriteByte('\n')
+		content = buf.Bytes()
+	}
+
+	_, err := w.Write(content)
+	return err
+}

cmd/oras/manifest/delete.go

@@ -14,24 +14,24 @@ limitations under the License.
 package manifest
 
 import (
-	"encoding/json"
 	"errors"
 	"fmt"
+	"os"
 
 	"github.com/spf13/cobra"
 	"oras.land/oras-go/v2/errdef"
 	ierrors "oras.land/oras/cmd/oras/internal/errors"
 	"oras.land/oras/cmd/oras/internal/option"
-	"oras.land/oras/cmd/oras/internal/util"
 )
 
 type deleteOptions struct {
 	option.Common
+	option.Confirmation
+	option.Descriptor
+	option.Pretty
 	option.Remote
 
-	confirmed  bool
-	descriptor bool
-	targetRef  string
+	targetRef string
 }
 
 func deleteCmd() *cobra.Command {
@@ -40,6 +40,7 @@ func deleteCmd() *cobra.Command {
 		Use:   "delete name[:tag|@digest]",
 		Short: "[Preview] Delete a manifest from remote registry",
 		Long: `[Preview] Delete a manifest from remote registry
+
 ** This command is in preview and under development. **
 
 Example - Delete a manifest tagged with 'latest' from repository 'locahost:5000/hello':
@@ -53,6 +54,9 @@ Example - Delete a manifest without TLS:
 `,
 		Args: cobra.ExactArgs(1),
 		PreRunE: func(cmd *cobra.Command, args []string) error {
+			if opts.OutputDescriptor && !opts.Confirmed {
+				return errors.New("must have --yes to confirm the deletion if output the descriptor")
+			}
 			return opts.ReadPassword()
 		},
 		RunE: func(_ *cobra.Command, args []string) error {
@@ -61,8 +65,6 @@ Example - Delete a manifest without TLS:
 		},
 	}
 
-	cmd.Flags().BoolVarP(&opts.confirmed, "yes", "y", false, "do not prompt for confirmation")
-	cmd.Flags().BoolVarP(&opts.descriptor, "descriptor", "", false, "print the descriptor of the manifest")
 	option.ApplyFlags(&opts, cmd.Flags())
 	return cmd
 }
@@ -87,9 +89,9 @@ func deleteManifest(opts deleteOptions) error {
 		return err
 	}
 
-	if !opts.confirmed {
-		fmt.Printf("Are you sure you want to delete the artifact '%v' and all manifests that refer to it? (y/n):", desc.Digest)
-		comfirmed, err := util.AskForComfirmation()
+	if !opts.Confirmed {
+		message := fmt.Sprintf("Are you sure you want to delete the artifact '%v' and all manifests that refer to it? (y/n):", desc.Digest)
+		comfirmed, err := opts.AskForComfirmation(message)
 		if err != nil {
 			return err
 		}
@@ -99,18 +101,18 @@ func deleteManifest(opts deleteOptions) error {
 	}
 
 	if err = repo.Delete(ctx, desc); err != nil {
-		return fmt.Errorf("failed to delete %s: %w", opts.targetRef, err)
+		return err
 	}
 
-	fmt.Println("Deleted", opts.targetRef)
-
-	if opts.descriptor {
-		descriptorByte, err := json.Marshal(desc)
+	if opts.OutputDescriptor {
+		bytes, err := opts.Marshal(desc)
 		if err != nil {
 			return err
 		}
-		fmt.Println(string(descriptorByte))
+		return opts.Output(os.Stdout, bytes)
 	}
 
+	fmt.Println("Deleted", opts.targetRef)
+
 	return nil
 }